Evaluation device, evaluation method, and non-transitory storage medium

ABSTRACT

An evaluation device includes a display for images; a gaze point detecting unit configured to detect a positional data of a gaze point of a subject; a display controller configured to display, on the display, a task target object and instruction information, and then a specific target object including a specific feature portion as a correct answer to the instruction information and comparison target objects; an area setting unit configured to set a specific feature area for the specific feature portion and comparison areas for the comparison target objects on the display; a determination unit configured to determine, based on the detected positional data, whether the gaze point is present in the set areas; an arithmetic unit configured to calculate, based on a determination result, a gaze point transition data; and an evaluating unit configured to obtain, based on the gaze point transition data, an evaluation data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2019/036425 filed on Sep. 17, 2019 which claims the benefit ofpriority from Japanese Patent Application No. 2018-248423 filed on Dec.28, 2018, the entire contents of which are incorporated herein byreference.

FIELD

The present application relates to an evaluation device, an evaluationmethod, and an evaluation program.

BACKGROUND

In recent years, it is said that cognitive functional impairment andbrain functional impairment are increasing, and a demand for detectingcognitive functional impairment and brain functional impairment earlyand a demand for quantitatively evaluating severity of symptoms arerequired. It is known that symptoms of cognitive functional impairmentand brain functional impairment affect cognitive ability. Therefore, anevaluation is performed on a subject based on cognitive ability of thesubject. For example, an apparatus that displays multiple numbers,instructs a subject to add the numbers to obtain an answer, and checksthe answer provided by the subject has been proposed (for example, seeJapanese Laid-open Patent Publication No. 2011-083403).

SUMMARY

However, in the method described in Patent Literature 1 or the like, thesubject selects an answer by operating a touch panel or the like and itis thus difficult to obtain high evaluation accuracy due to a correctanswer by chance or an error in operation performed by the subject.Therefore, there have been demands for evaluating cognitive functionalimpairment and brain functional impairment with high accuracy.

An evaluation device, an evaluation method, and a non-transitory storagemedium are disclosed.

According to one aspect, there is provided an evaluation devicecomprising: a display configured to display images; a gaze pointdetecting unit configured to detect a positional data of a gaze point ofa subject who observes the display; a display controller configured todisplay a task target object that includes a task feature portion andthat is to be gazed at by the subject and instruction information thatis a task related to the task target object on the display, and todisplay, after displaying the task target object and the instructioninformation, a specific target object that includes a specific featureportion corresponding to the task feature portion and that is a correctanswer to the instruction information and comparison target objects eachof which differs from the specific target object on the display; an areasetting unit configured to set a specific feature area for the specificfeature portion and comparison areas for the comparison target objectson the display; a determination unit configured to determine, based onthe positional data of the gaze point, whether the gaze point is presentin each of the specific feature area and the comparison areas; anarithmetic unit configured to calculate, based on a determination resultby the determination unit, a gaze point transition data in a targetdisplay period; and an evaluating unit configured to obtain, based onthe gaze point transition data in the target display period, anevaluation data of the subject.

According to one aspect, there is provided an evaluation methodcomprising: displaying images on a display; detecting a positional dataof a gaze point of a subject who observes the display; displaying a tasktarget object that includes a task feature portion and that is to begazed at by the subject and instruction information that is a taskrelated to the task target object on the display, and displaying, afterdisplaying the task target object and the instruction information, aspecific target object that includes a specific feature portioncorresponding to the task feature portion and that is a correct answerto the instruction information and comparison target objects each ofwhich differs from the specific target object on the display; setting aspecific feature area for the specific feature portion and comparisonareas for the comparison target objects on the display; determining,based on the positional data of the gaze point, whether the gaze pointis present in each of the specific feature area and the comparisonareas; calculating, based on a determination result, a gaze pointtransition data in a target display period; and obtaining, based on thegaze point transition data in the target display period, an evaluationdata of the subject.

According to one aspect, there is provided a non-transitory storagemedium that stores an evaluation program that causes a computer toexecute: a process of displaying images on a display; a process ofdetecting a positional data of a gaze point of a subject who observesthe display; a process of displaying a task target object that includesa task feature portion and that is to be gazed at by the subject andinstruction information that is a task related to the task target objecton the display, and displaying, after displaying the task target objectand the instruction information, a specific target object that includesa specific feature portion corresponding to the task feature portion andthat is a correct answer to the instruction information and comparisontarget objects each of which differs from the specific target object onthe display; a process of setting a specific feature area for thespecific feature portion and comparison areas for the comparison targetobjects on the display; a process of determining, based on thepositional data of the gaze point, whether the gaze point is present ineach of the specific feature area and the comparison areas; a process ofcalculating, based on a determination result, a gaze point transitiondata in a target display period; and a process of obtaining, based onthe gaze point transition data in the target display period, anevaluation data of the subject.

The above and other objects, features, advantages and technical andindustrial significance of this application will be better understood byreading the following detailed description of presently preferredembodiments of the application, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating an example of aline-of-sight detecting device according to one embodiment;

FIG. 2 is a diagram illustrating an example of a hardware configurationof the line-of-sight detecting device according to the embodiment;

FIG. 3 is a functional block diagram illustrating an example of theline-of-sight detecting device according to the embodiment;

FIG. 4 is a schematic diagram illustrating a method for calculating apositional data of a corneal curvature center according to theembodiment;

FIG. 5 is a schematic diagram illustrating a method for calculating apositional data of a corneal curvature center according to theembodiment;

FIG. 6 is a schematic diagram illustrating an example of a calibrationprocess according to the embodiment;

FIG. 7 is a schematic diagram illustrating an example of a gaze pointdetecting process according to the embodiment;

FIG. 8 is a diagram illustrating an example of content that is displayedon a display in an instruction display operation;

FIG. 9 is a diagram illustrating an example of a case in which multipletarget objects are displayed on the display in a target displayoperation;

FIG. 10 is a diagram illustrating another example of content that isdisplayed on the display in the instruction display operation;

FIG. 11 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display in the targetdisplay operation;

FIG. 12 is a diagram illustrating another example of content that isdisplayed on the display in the instruction display operation;

FIG. 13 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display in the targetdisplay operation;

FIG. 14 is a flowchart illustrating an example of an evaluation method;

FIG. 15 is a flowchart illustrating an example of an evaluation methodin the target display operation;

FIG. 16 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display in the targetdisplay operation;

FIG. 17 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display in the targetdisplay operation;

FIG. 18 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display in the targetdisplay operation;

FIG. 19 is a flowchart illustrating another example of the evaluationmethod in the target display operation;

FIG. 20 is a flowchart illustrating another example of the evaluationmethod in the instruction display operation; and

FIG. 21 is a flowchart illustrating another example of the evaluationmethod in the target display operation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of an evaluation device, an evaluation method, andan evaluation program according to the present disclosure will bedescribed based on the drawings. Furthermore, the present application isnot limited to the embodiments. Furthermore, the components described inthe embodiments include one that can easily be replaced by those skilledin the art or one that is substantially identical.

In a description below, the positional relationships among componentswill be described by setting a three-dimensional global coordinatesystem. It is assumed that a direction parallel to a first axis of apredetermined plane is defined as an X-axis direction, a directionparallel to a second axis of the predetermined plane orthogonal to thefirst axis is defined as a Y-axis direction, and a direction parallel toa third axis that is orthogonal to each of the first axis and the secondaxis is defined as a Z-axis direction. The predetermined plane includesan XY plane.

Line-of-Sight Detecting Device

FIG. 1 is a perspective view schematically illustrating an example of aline-of-sight detecting device 100 according to a first embodiment. Theline-of-sight detecting device 100 is used as an evaluation device thatevaluates cognitive functional impairment and brain functionalimpairment. As illustrated in FIG. 1, the line-of-sight detecting device100 includes a display device 101, a stereo camera device 102, and anilluminating device 103.

The display device 101 includes a flat panel display, such as a liquidcrystal display (LCD) or an organic electro-luminescence (EL) display(OLED). In the embodiment, the display device 101 includes a display101S. The display 101S displays an image. In the embodiment, the display101S displays an index for evaluating, for example, a visual performanceof a subject. The display 101S is substantially parallel to the XYplane. The X-axis direction corresponds to the horizontal direction ofthe display 101S, the Y-axis direction corresponds to the verticaldirection of the display 101S, and the Z-axis direction corresponds tothe depth direction orthogonal to the display 101S.

The stereo camera device 102 includes a first camera 102A and a secondcamera 102B. The stereo camera device 102 is arranged below the display101S of the display device 101. The first camera 102A and the secondcamera 102B are arranged in the X-axis direction. The first camera 102Ais arranged in the negative X direction relative to the second camera102B. Each of the first camera 102A and the second camera 102B includesan infrared camera and includes, an optical system capable oftransmitting near-infrared light with a wavelength of, for example, 850(nm) and an image sensor capable of receiving the near-infrared light.

The illuminating device 103 includes a first light source 103A and asecond light source 103B. The illuminating device 103 is arranged belowthe display 101S of the display device 101. The first light source 103Aand the second light source 103B are arranged in the X-axis direction.The first light source 103A is arranged in the negative directionrelative to the first camera 102A. The second light source 103B isarranged in the positive direction relative to the second camera 102B.Each of the first light source 103A and the second light source 103Bincludes a light emitting diode (LED) light source and is able to emitnear-infrared light with a wavelength of, for example, 850 (nm).Furthermore, the first light source 103A and the second light source103B may also be arranged between the first camera 102A and the secondcamera 102B.

The illuminating device 103 emits near-infrared light that is detectionlight and illuminates an eyeball 111 of a subject. The stereo cameradevice 102 captures an image of a part of the eyeball 111 (hereinafter,referred to as an “eyeball” including the part of the eyeball) by thesecond camera 102B when the eyeball 111 is irradiated with the detectionlight emitted from the first light source 103A and captures an image ofthe eyeball 111 by the first camera 102A when the eyeball 111 isirradiated with the detection light emitted from the second light source103B.

A frame synchronization signal is output from at least one of the firstcamera 102A and the second camera 102B. The first light source 103A andthe second light source 103B output detection light based on the framesynchronization signal. The first camera 102A captures image data of theeyeball 111 when the eyeball 111 is irradiated with the detection lightemitted from the second light source 103B. The second camera 102Bcaptures image data of the eyeball 111 when the eyeball 111 isirradiated with the detection light emitted from the first light source103A.

When the eyeball 111 is irradiated with the detection light, a part ofthe detection light is reflected at a pupil 112 and the light from thepupil 112 is incident into the stereo camera device 102. Furthermore,when the eyeball 111 is irradiated with the detection light, a cornealreflection image 113 that is a virtual image of a cornea is formed onthe eyeball 111 and the light from the corneal reflection image 113 isincident into the stereo camera device 102.

By appropriately setting the relative position between a set of thefirst camera 102A and the second camera 102B and a set of the firstlight source 103A and the second light source 103B, the intensity of thelight incident from the pupil 112 to the stereo camera device 102 isreduced and the intensity of the light incident from the cornealreflection image 113 to the stereo camera device 102 is increased. Thatis, the image of the pupil 112 captured by the stereo camera device 102has a low luminance and the image of the corneal reflection image 113has a high luminance. The stereo camera device 102 can detect theposition of the pupil 112 and a position of the corneal reflection image113 based on the luminance of the image captured.

FIG. 2 is a diagram illustrating an example of a hardware configurationof the line-of-sight detecting device 100 according to the embodiment.As illustrated in FIG. 2, the line-of-sight detecting device 100includes the display device 101, the stereo camera device 102, theilluminating device 103, a computer system 20, an input/output interfacedevice 30, a driving circuit 40, an output device 50, and an inputdevice 60.

The computer system 20, the driving circuit 40, the output device 50,and the input device 60 perform data communication via the input/outputinterface device 30. The computer system 20 includes an arithmeticprocessing device 20A and a storage device 20B. The arithmeticprocessing device 20A includes a microprocessor, such as a centralprocessing unit (CPU). The storage device 20B includes a memory, such asa read only memory (ROM) and a random access memory (RAM), or storage.The arithmetic processing device 20A performs arithmetic processing inaccordance with a computer program 20C that is stored in the storagedevice 20B.

The driving circuit 40 generates a driving signal and outputs thedriving signal to the display device 101, the stereo camera device 102,and the illuminating device 103. Furthermore, the driving circuit 40supplies the image data of the eyeball 111 captured by the stereo cameradevice 102 to the computer system 20 via the input/output interfacedevice 30.

The output device 50 includes a display, such as a flat panel display.Furthermore, the output device 50 may also include a printer. The inputdevice 60 generates input data by being operated. The input device 60includes a keyboard or a mouse for a computer system. Furthermore, theinput device 60 may also include a touch sensor arranged on the displayof the output device 50 as a display.

In the embodiment, the display device 101 and the computer system 20 areseparated devices. Furthermore, the display device 101 and the computersystem 20 may also be integrated. For example, if the line-of-sightdetecting device 100 includes a tablet type personal computer, thecomputer system 20, the input/output interface device 30, the drivingcircuit 40, and the display device 101 may also be mounted on the tablettype personal computer.

FIG. 3 is a functional block diagram illustrating an example of theline-of-sight detecting device 100 according to the embodiment. Asillustrated in FIG. 3, the input/output interface device 30 includes aninput/output unit 302. The driving circuit 40 includes a display devicedriving unit 402 that generates a driving signal for driving the displaydevice 101 and that outputs the driving signal to the display device101; a first camera input/output unit 404A that generates a drivingsignal for driving the first camera 102A and that outputs the drivingsignal to the first camera 102A; a second camera input/output unit 404Bthat generates a driving signal for driving the second camera 102B andthat outputs the driving signal to the second camera 102B; and a lightsource driving unit 406 that generates a driving signal for driving thefirst light source 103A and the second light source 103B and thatoutputs the driving signal to the first light source 103A and the secondlight source 103B. Furthermore, the first camera input/output unit 404Asupplies the image data of the eyeball 111 captured by the first camera102A to the computer system 20 via the input/output unit 302. The secondcamera input/output unit 404B supplies the image data of the eyeball 111captured by the second camera 102B to the computer system 20 via theinput/output unit 302.

The computer system 20 controls the line-of-sight detecting device 100.The computer system 20 includes a display controller 202, a light sourcecontroller 204, an image data acquiring unit 206, an input dataacquiring unit 208, a position detecting unit 210, a curvature centercalculating unit 212, a gaze point detecting unit 214, an area settingunit 216, a determination unit 218, an arithmetic unit 220, a storage222, an evaluation unit 224, and an output controller 226. The functionof the computer system 20 is performed by the arithmetic processingdevice 20A and the storage device 20B.

The display controller 202 performs an instruction display operation ofdisplaying, on the display 101S, a task target object that is to begazed at by the subject and instruction information that is a taskrelated to the task target object. The task target object includes atask feature portion. The task feature portion is a portion that can bean appearance feature when the subject memorizes the task featureportion. For example, a recess portion or a protruding portion of apattern that constitutes the task target object or a connection portionor the like of multiple patterns can be used as the task featureportion. Examples of the connection portion of the multiple patternsinclude an overlapping portion, a contact portion, an intersectionportion, and the like of the multiple patterns. The instructioninformation includes characters, a figure, and the like that are able tobe displayed on the display 101S. An example of the task includes a taskthat allows the subject to memorize the task target object and selectthe same target object as the memorized task target object.

Furthermore, after the instruction display operation, the displaycontroller 202 performs a target display operation of displaying, on thedisplay 101S, a specific target object that is a correct answer to theinstruction information and comparison target objects each of whichdiffers from the specific target object. The specific target objectincludes a specific feature portion that is associated with the taskfeature portion. Similarly to the task feature portion, a recess portionor a protruding portion of the pattern that constitutes the specifictarget object or a connection portion or the like of multiple patternscan be used as the specific feature portion. Examples of the connectionportion of the multiple patterns include an overlapping portion, acontact portion, and an intersection portion. Furthermore, for example,if a task that allows the subject to select the same target object asthe memorized task target object is given as described above, thespecific target object corresponds to the same target object as the tasktarget object in appearance. Therefore, in this case, the specificfeature portion is the same portion as the task feature portion.

The task target object, the instruction information, the specific targetobject, and the comparison target objects are included in, for example,an evaluation purpose video or an evaluation purpose image that is to bevisually confirmed by the subject. The display controller 202 displaysthe evaluation purpose video or the evaluation purpose image on thedisplay 101S. Furthermore, the instruction information is not limited toa mode that uses, for example, a sentence using characters. Theinstruction information may also be a mode that uses, for example, acombination of figures without using characters as long as theinstruction information is able to convey the task to the subject.

The light source controller 204 controls the light source driving unit406 and controls an operation state of the first light source 103A andthe second light source 103B. The light source controller 204 controlsthe first light source 103A and the second light source 103B such thatthe first light source 103A and the second light source 103B emit thedetection light at different timings.

The image data acquiring unit 206 acquires, from the stereo cameradevice 102 via the input/output unit 302, the image data of the eyeball111 of the subject captured by the stereo camera device 102 thatincludes the first camera 102A and the second camera 102B.

The input data acquiring unit 208 acquires, from the input device 60 viathe input/output unit 302, the input data generated by an operation ofthe input device 60.

The position detecting unit 210 detects positional data of the pupilcenter based on the image data of the eyeball 111 acquired by the imagedata acquiring unit 206. Furthermore, the position detecting unit 210detects positional data of the corneal reflection center based on theimage data of the eyeball 111 acquired by the image data acquiring unit206. The pupil center is a center of the pupil 112. The cornealreflection center is a center of the corneal reflection image 113. Theposition detecting unit 210 detects, for each of the left and righteyeballs 111 of the subject, the positional data of the pupil center andthe positional data of the corneal reflection center.

The curvature center calculating unit 212 calculates positional data ofa corneal curvature center of the eyeball 111 based on the image data ofthe eyeball 111 acquired by the image data acquiring unit 206.

The gaze point detecting unit 214 detects positional data of the gazepoint P of the subject based on the image data of the eyeball 111acquired by the image data acquiring unit 206. In the presentembodiment, the positional data of the gaze point P indicates thepositional data of an intersection point between a line-of-sight vectorof the subject that is defined by the three-dimensional globalcoordinate system and the display 101S of the display device 101. Thegaze point detecting unit 214 detects a line-of-sight vector of each ofthe right and left eyeballs 111 of the subject based on the positionaldata of the pupil center and the positional data of the cornealcurvature center that are acquired from the image data of the eyeball111. After the line-of-sight vector has been detected, the gaze pointdetecting unit 214 detects the positional data of the gaze point Pindicating the intersection point between the line-of-sight vector andthe display 101S.

The area setting unit 216 sets, on the display 101S, in an instructiondisplay period for which the instruction display operation is beingperformed, a task feature area for the task feature portion of the tasktarget object and an instruction area for the instruction information.Furthermore, the area setting unit 216 sets, on the display 101S, in thetarget display period for which the target display operation is beingperformed, a specific feature area for the specific feature portion ofthe specific target object and comparison areas for the comparisontarget objects.

The determination unit 218 determines, in the instruction displayperiod, based on the positional data of the gaze point P, whether thegaze point P is present in each of the task feature area and theinstruction area, and then, outputs determination data. Thedetermination unit 218 determines whether the gaze point P is present ineach of the task feature area and the instruction area at, for example,regular intervals. Furthermore, the determination unit 218 determines,in the target display period, based on the positional data of the gazepoint P, whether the gaze point P is present in each of the specificfeature area and the comparison areas, and then, outputs determinationdata. The determination unit 218 determines whether the gaze point P ispresent in each of the specific area and the comparison areas at, forexample, regular intervals. The regular interval is, for example, aperiod (for example, every 20 (msec)) of a frame synchronization signalthat is output from each of the first camera 102A and the second camera102B.

The arithmetic unit 220 calculates, based on the determination data bythe determination unit 218, a gaze point transition data in theinstruction display period that indicates a transition of the gaze pointP in the instruction display period. Furthermore, the arithmetic unit220 calculates, based on the determination data by the determinationunit 218, a gaze point transition data in the target display period thatindicates a transition of the gaze point P in the target display period.

The gaze point transition data in the instruction display periodincludes a first presence time data that indicates a presence time inwhich the gaze point P is present in the task feature area in theinstruction display period, a second presence time data that indicates apresence time in which the gaze point P is present in the instructionarea in the instruction display period, an arrival time data in theinstruction display period that indicates a time period from a starttime of the instruction display period to an arrival time at which thegaze point P arrives at the task feature area, and a moving frequencydata in the instruction display period that indicates the number oftimes of position movement of the gaze point P between the task featurearea and the instruction area.

The gaze point transition data in the target display period includes anarrival time data in the target display period that indicates a timeperiod from a start time of the target display period to an arrival timeat which the gaze point P arrives at the specific feature area, a movingfrequency data in the target display period that indicates the number oftimes of position movement of the gaze point P between multiplecomparison areas until the gaze point P first arrives at the specificfeature area, a presence time data in the target display period thatindicates a presence time in which the gaze point P is present in thespecific feature area in the target display period, and a final areadata that indicates an area in which the gaze point P is finally presentamong the specific feature area and the comparison areas in the targetdisplay period.

Furthermore, the arithmetic unit 220 includes a management timer thatmanages a playback time of a video and a detection timer T1 that detectsan elapsed time from displaying the video on the display 101S. Thearithmetic unit 220 includes a counter that counts the number ofdetermination that the gaze point P is present in the specific area.

The evaluation unit 224 obtains evaluation data of the subject based onthe gaze point transition data in the target display period.Furthermore, the evaluation unit 224 is able to obtain the evaluationdata of the subject based on the gaze point transition data in theinstruction display period and the gaze point transition data in thetarget display period. The evaluation data includes data that is used toevaluate, in the instruction display operation, whether the subject isable to gaze at the task target object and the instruction informationthat are displayed on the display 101S. Furthermore, the evaluation dataincludes data that is used to evaluate, in the target display operation,whether the subject is able to gaze at the specific target object andthe comparison target objects that are displayed on the display 101S.

The storage 222 stores therein the determination data, the gaze pointtransition data in the instruction display period (the first presencetime data, the second presence time data, the arrival time data in theinstruction display period, and the movement frequency data in theinstruction display period), the gaze point transition data in thetarget display period (the presence time data in the target displayperiod, the movement frequency data in the target display period, thefinal area data, and the arrival time data in the target displayperiod), and the evaluation data, which are described above.Furthermore, the storage 222 stores therein an evaluation program thatcauses a computer to execute a process of displaying an image on thedisplay 101S; a process of detecting the positional data of the gazepoint P of the subject who observes the display 101S; a process ofdisplaying, after displaying the task target object that includes thetask feature portion and that is to be gazed at by the subject and theinstruction information that is a task for the task target object on thedisplay 101S, the specific target object that includes the specificfeature portion for the task feature portion and corresponds to acorrect answer to the instruction information and the comparison targetobjects that differs from the specific target object on the display101S; a process of setting, on the display 101S, the specific featurearea for the specific feature portion and the comparison areas for thecomparison target objects; a process of determining, based on thepositional data of the gaze point P, whether the gaze point P is presentin each of the specific feature area and the comparison areas; a processof calculating, based on the determination result, the gaze pointtransition data in the target display period; and a process ofobtaining, based on the gaze point transition data in the target displayperiod, evaluation data of the subject.

The output controller 226 outputs the data to at least one of thedisplay device 101 and the output device 50.

In the following, an outline of processes performed by the curvaturecenter calculating unit 212 according to the embodiment will bedescribed. The curvature center calculating unit 212 calculates thepositional data of the corneal curvature center of the eyeball 111 basedon the image data of the eyeball 111. Each of FIG. 4 and FIG. 5 is aschematic diagram illustrating a calculation method of positional dataof a corneal curvature center 110 according to the embodiment. FIG. 4illustrates an example in which the eyeball 111 is illuminated by alight source 103C. FIG. 5 illustrates an example in which the eyeball111 is illuminated by the first light source 103A and the second lightsource 103B.

First, the example illustrated in FIG. 4 will be described. The lightsource 103C is arranged between the first camera 102A and the secondcamera 102B. A pupil center 112C is a center of the pupil 112. A cornealreflection center 113C is a center of the corneal reflection image 113.In FIG. 4, the pupil center 112C indicates a pupil center when theeyeball 111 is illuminated by the single light source 103C. The cornealreflection center 113C indicates a corneal reflection center when theeyeball 111 is illuminated by the single light source 103C. The cornealreflection center 113C is present on a straight line connecting thelight source 103C and a corneal curvature center 110. The cornealreflection center 113C is positioned at a middle point between a corneasurface and the corneal curvature center 110. A corneal curvature radius109 is a distance between the cornea surface and the corneal curvaturecenter 110. Positional data of the corneal reflection center 113C isdetected by the stereo camera device 102. The corneal curvature center110 is present on a straight line connecting the light source 103C andthe corneal reflection center 113C. The curvature center calculatingunit 212 calculates, as the positional data of the corneal curvaturecenter 110, positional data of a position which is located at apredetermined distance from the corneal reflection center 113C on thestraight line. The predetermined value is a value that is determined inadvance from a curvature radius value of a general cornea or the likeand is stored in the storage 222.

In the following, the example illustrated in FIG. 5 will be described.In the embodiment, a set of the first camera 102A and the second lightsource 103B and a set of the second camera 102B and the first lightsource 103A are arranged at bilaterally symmetrical positions withrespect to a straight line that passes through an intermediate positionbetween the first camera 102A and the second camera 102B. It is assumedthat a virtual light source 103V is present at the intermediate positionbetween the first camera 102A and the second camera 102B. A cornealreflection center 121 indicates a corneal reflection center in an imagethat is obtained by capturing the eyeball 111 by the second camera 102B.A corneal reflection center 122 indicates a corneal reflection center inan image that is obtained by capturing the eyeball 111 by the firstcamera 102A. A corneal reflection center 124 indicates a cornealreflection center associated with the virtual light source 103V.Positional data of the corneal reflection center 124 is calculated basedon positional data of the corneal reflection center 121 and positionaldata of the corneal reflection center 122 that are captured by thestereo camera device 102. The stereo camera device 102 detects thepositional data of the corneal reflection center 121 and the positionaldata of the corneal reflection center 122 in the three-dimensional localcoordinate system that is defined in the stereo camera device 102. Acamera calibration using a stereo calibration method is performed inadvance on the stereo camera device 102, and a transformation parameterfor transforming the three dimensional local coordinate system of thestereo camera device 102 into the three-dimensional global coordinatesystem is calculated. The transformation parameter is stored in thestorage 222. The curvature center calculating unit 212 transforms thepositional data of the corneal reflection center 121 and the positionaldata of the corneal reflection center 122 captured by the stereo cameradevice 102 into the positional data in the three-dimensional globalcoordinate system by using the transformation parameter. The curvaturecenter calculating unit 212 calculates the positional data of thecorneal reflection center 124 in the three-dimensional global coordinatesystem based on the positional data of the corneal reflection center 121and the positional data of the corneal reflection center 122 that aredefined in the three-dimensional global coordinate system. The cornealcurvature center 110 is present on a straight line 123 connecting thevirtual light source 103V and the corneal reflection center 124. Thecurvature center calculating unit 212 calculates, as the positional dataof the corneal curvature center 110, positional data of a position whichis located at a predetermined distance from the corneal reflectioncenter 124 on the straight line 123. The predetermined value is a valuethat is determined in advance from a curvature radius value of a generalcornea or the like and is stored in the storage 222.

In this way, even when two light sources are present, the cornealcurvature center 110 is calculated by the same method as the method thatis used when a single light source is present.

The corneal curvature radius 109 corresponds to a distance between thecornea surface and the corneal curvature center 110. Accordingly, thecorneal curvature radius 109 is calculated by calculating the positionaldata of the cornea surface and the positional data of the cornealcurvature center 110.

In the following, an example of a line-of-sight detecting methodaccording to the embodiment will be described. FIG. 6 is a schematicdiagram illustrating an example of a calibration process according tothe embodiment. In the calibration process, a target position 130 is setin order to allow the subject to gaze steadily. The target position 130is defined in the three-dimensional global coordinate system. In theembodiment, the target position 130 is set at, for example, a middleposition of the display 101S of the display device 101. Furthermore, thetarget position 130 may also be set at an edge position of the display101S. The output controller 226 displays a target image at the settarget position 130. A straight line 131 is a straight line connectingthe virtual light source 103V and the corneal reflection center 113C. Astraight line 132 is a straight line connecting the target position 130and the pupil center 112C. The corneal curvature center 110 is anintersection point between the straight line 131 and the straight line132. The curvature center calculating unit 212 can calculate thepositional data of the corneal curvature center 110 based on thepositional data of the virtual light source 103V, the positional data ofthe target position 130, the positional data of the pupil center 112C,and the positional data of the corneal reflection center 113C.

In the following, a gaze point detecting process performed by the gazepoint detecting unit 214 will be described. The gaze point detectingprocess is performed after the calibration process. The gaze pointdetecting unit 214 calculates a line-of-sight vector of the subject andpositional data of the gaze point P based on the image data of theeyeball 111. FIG. 7 is a schematic diagram illustrating an example ofthe gaze point detecting process according to the embodiment. In FIG. 7,a gaze point 165 indicates a gaze point P that is obtained from thecorneal curvature center calculated using a general curvature radiusvalue. A gaze point 166 indicates a gaze point P that is obtained fromthe corneal curvature center calculated using a distance 126 obtained inthe calibration process. The pupil center 112C indicates the pupilcenter calculated in the calibration process, and the corneal reflectioncenter 113C indicates the corneal reflection center calculated in thecalibration process. A straight line 173 is a straight line connectingthe virtual light source 103V and the corneal reflection center 113C.The corneal curvature center 110 corresponds to a position of thecorneal curvature center that is calculated from a general curvatureradius value. The distance 126 is a distance between the pupil center112C and the corneal curvature center 110 calculated in the calibrationprocess. A corneal curvature center 110H indicates a corrected positionof the corneal curvature center that has been corrected by using thedistance 126. The corneal curvature center 110H is obtained under acondition that the corneal curvature center 110 is present on thestraight line 173 and the distance between the pupil center 112C and thecorneal curvature center 110 is the distance 126. Accordingly, a line ofsight 177 that is calculated in a case of using the general curvatureradius value is corrected to a line of sight 178. Furthermore, the gazepoint P on the display 101S of the display device 101 is corrected fromthe gaze point 165 to the gaze point 166.

Evaluation Method

In the following, the evaluation method according to the embodiment willbe described. In the evaluation method according to the embodiment, adevelopmental disability is evaluated as a visual performance of thesubject by using the line-of-sight detecting device 100 described above.

FIG. 8 is a diagram illustrating an example of content that is displayedon the display 101S in the instruction display operation. As illustratedin FIG. 8, the display controller 202 displays, on the display 101S inthe instruction display operation, a task target object M01 that is tobe gazed at by the subject and instruction information I1 that instructsthe subject to accomplish a task for the task target object M01. In thiscase, a task with content that instructs to memorize a figure of thetask target object M01 and select the same target object as thememorized task target object M01 is indicated as an example. In thiscase, the display controller 202 is able to display, on the display101S, the task target object M01 and the instruction information I1 soas not to overlap with each other. In the example illustrated in FIG. 8,the task target object M01 has a shape of a combination of multiplepatterns. Specifically, the task target object M01 has a shape of acombination of a circle and an equilateral triangle and one of thevertices of the equilateral triangle is brought into contact with acircumference of the circle. In the task target object M01, the contactportion in which the one of the vertices of the equilateral triangle isbrought into contact with the circumference of the circle is a portionthat can be an appearance feature when the subject memorizes the tasktarget object M01, i.e., a task feature portion C01.

In the instruction display period for which the instruction displayoperation is being performed, the area setting unit 216 sets a taskfeature area A in a rectangular region that includes, for example, thetask feature portion C01 of the task target object M01. The task featurearea A does not need to include an entirety of the task target object M1as long as the task feature area A includes a part of the task featureportion C01. Furthermore, the area setting unit 216 sets an instructionarea B in a rectangular region that includes, for example, theinstruction information I1. The area setting unit 216 sets the taskfeature area A and the instruction area B on the display 101S atpositions such that these areas do not overlap with each other.Furthermore, the shape of each of the task feature area A and theinstruction area B is not limited to a rectangle, and the shape thereofmay also be another shape, such as a circular shape, an ellipticalshape, or a polygonal shape.

FIG. 9 is a diagram illustrating an example of a case in which multipletarget objects are displayed on the display 101S in the target displayoperation. After the display controller 202 performs the instructiondisplay operation in a predetermined period of time, the displaycontroller 202 displays, on the display 101S as the target displayoperation, as illustrated in FIG. 9, a specific target object M1 that isa correct answer to the instruction information I1 and multiplecomparison target objects M2 to M4 that are incorrect answers to theinstruction information I1.

Here, when based on the content of the instruction information I1, thetask target object M01 and the specific target object M1 are the sametarget object in appearance. Therefore, similarly to the task targetobject M01, the specific target object M1 has a shape of a combinationof a circle and an equilateral triangle and one of the vertices of theequilateral triangle is brought into contact with the circumference ofthe circle. The comparison target objects M2 to M4 may also have theshape that is similar to the shape of the specific target object M1 ormay also have the shape that is not similar to the shape of the specifictarget object M1. In the example illustrated in FIG. 9, the comparisontarget object M2 has a shape of a combination of a trapezoid and acircle, the comparison target object M3 has a shape of a combination ofa square and a circle, and the comparison target object M4 has a shapeof a combination of a circle and a regular hexagon. The displaycontroller 202 displays, on the display 101S, the multiple targetobjects including the specific target object M1 and the comparisontarget objects M2 to M4, thereby allowing the subject to find thespecific target object M1 and gaze at the found specific target objectM1.

Furthermore, FIG. 9 illustrates an example of a gaze point P that isdisplayed on the display 101S as a result of a measurement. However, inpractice, the gaze point P is not displayed on the display 101S.Detection of the positional data of the gaze point P is performed in,for example, a period (for example, every 20 (msec)) of a framesynchronization signal that is output from the first camera 102A and thesecond camera 102B. The first camera 102A and the second camera 102Bcapture an image in synchronization.

In the target display period for which the target display operation isbeing performed, the area setting unit 216 sets a specific feature areaA1 for a specific feature portion C1 of the specific target object M1.The specific feature portion C1 is a portion corresponding to the taskfeature portion C01 of the task target object M01. Here, the specificfeature portion C1 of the specific target object M1 corresponds to thesame portion as the task feature portion C01 of the task target objectM01. Namely, in the specific target object M1, the contact portion inwhich one of the vertices of the equilateral triangle is brought intocontact with the circumference of the circle corresponds to the specificfeature portion C1. Furthermore, the area setting unit 216 setscomparison areas A2 to A4 in the rectangular region for the comparisontarget objects M2 to M4, respectively. Furthermore, the specific featurearea A1 and the comparison areas A2 to A4 are not displayed on thedisplay 101S. Furthermore, the shape of each of the specific featurearea A1 and comparison areas A2 to A4 is not limited to a rectangle andthe shape thereof may also be another shape, such as a circular shape,an elliptical shape, or a polygonal shape.

It is known that symptoms of cognitive functional impairment and brainfunctional impairment affect cognitive ability and memory ability of thesubject. If the subject does not have cognitive functional impairmentand brain functional impairment, after the subject viewed theinstruction information I1 that is displayed on the display 101S in theinstruction display operation, the subject attempts to memorize theshape of the task target object M01 by gazing at the task target objectM01 indicated by the instruction information I1. Furthermore, if thesubject does not have cognitive functional impairment and brainfunctional impairment, the subject is able to view the comparison targetobjects M2 to M4 one by one displayed on the display 101S in the targetdisplay operation, compare the task target object M01 memorized in theinstruction display operation with the viewed comparison target objectsM2 to M4, determine that these objects are not the same, finally findout the specific target object M1, and gaze at the found object.Furthermore, if the subject is not cognitive functional impairment andbrain functional impairment, the subject tends to gaze at and memorizethe task feature portion C01 of the task target object M01 in theinstruction display operation, and make the determination by gazing thespecific feature portion C1 of the specific target object M1 in thetarget display operation.

In contrast, if the subject has cognitive functional impairment andbrain functional impairment, in the instruction display operation, thesubject tends not to concentratedly view the task target object M01 byconsecutively viewing the instruction information I1 or by alternatelyviewing the instruction information I1 and the task target object M01.Furthermore, if the subject has cognitive functional impairment andbrain functional impairment, in some cases, the subject is not able tomemorize the specific target object M1 in the instruction displayoperation or forgets the specific target object M1 immediately even ifthe subject memorizes the specific target object M1. Thus, it isdifficult to make a comparison described above in the target displayoperation and, in some cases, the subject is not able to gaze at thespecific target object M1.

Furthermore, in the target display operation, with a method fordisplaying the multiple target objects M1, M2, M3, and M4 on the display101S, there may be a case in which, at the start of the target displayoperation, the gaze point P of the subject is accidentally placed at thespecific target object M1 that is a correct answer. In such a case,since there is a possibility of determining that the subject found thecorrect answer regardless of whether the subject is cognitive functionalimpairment and brain functional impairment, it is difficult to evaluatethe subject with high accuracy. Accordingly, for example, it is possibleto evaluate the subject by performing the following processes.

First, as the instruction display operation, the display controller 202displays the task target object M01 that includes the task featureportion C01 and the instruction information I1 on the display 101S. Inthis case, it is possible to evaluate the subject from a viewpointwhether, after the subject viewed the instruction information I1displayed on the display 101S, the subject attempts to memorize theshape of the task target object M01 by gazing at the task featureportion C01 of the task target object M01 indicated by the instructioninformation I1. Furthermore, on the other hand, it is possible toevaluate the subject from a viewpoint, in the instruction displayoperation, whether the subject consecutively views the instructioninformation I1, whether the subject alternately views the instructioninformation I1 and the task target object M01, and whether the subjectdoes not concentratedly view the task target object M01 and the taskfeature portion C01.

Furthermore, as the target display operation, it is assumed to be in astate in which the specific target object M1 and the multiple comparisontarget objects M2 to M4 are displayed on the display 101S. In this case,it is possible to evaluate the subject from a viewpoint whether thesubject gazes at the multiple comparison target objects M2 to M4 one byone, whether the subject is able to finally reach the specific targetobject M1 that is a correct answer, how long does it take before thesubject reaches the specific target object M1, and whether the subjectis able to gaze at the specific feature portion C1 of the specifictarget object M1.

For example, in the instruction display operation, when a positionaldata of the gaze point P of the subject is detected, the determinationunit 218 determines whether the gaze point P of the subject is presentin the task feature area A and the instruction area B, and then, outputsdetermination data.

The arithmetic unit 220 calculates, based on the determination data, thegaze point transition data in the instruction display period thatindicates the transition of the gaze point P in the instruction displayperiod. The arithmetic unit 220 calculates, as the gaze point transitiondata in the instruction display period, the first presence time data,the second presence time data, the arrival time data in the instructiondisplay period, and the movement frequency data in the instructiondisplay period.

The first presence time data indicates a presence time in which the gazepoint P is present in the task feature area A. In the embodiment, whenthe determination unit 218 determines whether the gaze point P ispresent in the task feature area A and the instruction area B at, forexample, regular intervals, it is possible to estimate that the presencetime in which the gaze point P is present in the task feature area A islonger as the number of determination that the gaze point P is presentin the task feature area A is increased. Therefore, it is possible touse, as the first presence time data, the number of the determinationthat the gaze point P is present in the task feature area A by thedetermination unit 218. Namely, the arithmetic unit 220 is able to use acount value CNTA of the counter as the first presence time data.

The second presence time data indicates a presence time in which thegaze point P is present in the instruction area B. In the embodiment,when the determination unit 218 determines whether the gaze point P ispresent in the task feature area A and the instruction area B at, forexample, regular intervals, it is possible to estimate that the presencetime in which the gaze point P is present in the instruction area B islonger as the number of determination that the gaze point P is presentin the instruction area B is increased. Therefore, it is possible touse, as the second presence time data, the number of the determinationthat the gaze point P is present in the instruction area B by thedetermination unit 218. Namely, the arithmetic unit 220 is able to use acount value CNTB of the counter as the second presence time data.

The arrival time data in the instruction display period indicates aperiod of time from a start time of the instruction display period to anarrival time at which the gaze point P first arrives at the task featurearea A. Therefore, by measuring an elapsed time from the start of theinstruction display period by the timer T1, and detecting a measurementvalue of the timer T1 when the gaze point P first arrives at the taskfeature area A with setting a flag value to 1, the arithmetic unit 220is able to use a detection result of the timer T1 as the arrival timedata in the instruction display period.

The movement frequency data in the instruction display period indicatesthe number of movement of the gaze point P between the task feature areaA and the instruction area B. Therefore, the arithmetic unit 220 is ableto count the number of movement of the gaze point P in the areas betweenthe task feature area A and the instruction area B and use a countresult as the movement frequency data in the instruction display period.

Regarding the instruction display operation, the evaluation unit 224obtains evaluation data based on the first presence time data, thesecond presence time data, the arrival time data in the instructiondisplay period, and the movement frequency data in the instructiondisplay period.

Here, a data value based on the first presence time data is denoted byD11, a data value based on the second presence time data is denoted byD12, a data value based on the arrival time data in the instructiondisplay period is denoted by D13, and a data value based on the movementfrequency data in the instruction display period is denoted by D14.However, it is assumed that the data value D11 based on the firstpresence time data is the number of seconds in which the gaze point P ispresent in the task feature area A and, when the value thereof isgreater than or equal to a predetermined upper limit a, a is set.Furthermore, it is assumed that the data value D12 based on the secondpresence time data is a value obtained by subtracting the number ofseconds in which the gaze point P is present in the instruction area Bfrom the above described value a. Furthermore, it is assumed that thedata value D13 based on the arrival time data in the instruction displayperiod is set to an inverse number of the arrival time (for example,1/(arrival time)/10) (10 is a coefficient for setting an arrival timeevaluation value to 1 or less based on an assumption that a minimumvalue of the arrival time is 0.1 second). Furthermore, it is assumedthat the data value D14 based on the movement frequency data in theinstruction display period is a value obtained by subtracting the countvalue from 1. Furthermore, if the data value D14 is calculated, an upperlimit may also be set to the count value that is subtracted from 1.

In this case, an evaluation value ANS may be represented, for example,as follows;

ANS 1 = D 11 ⋅ K 11 + D 12 ⋅ K 12 + D 13 ⋅ K 13 + D 14 ⋅ K 14

K11 to K14 are constants for weighting. The constants K11 to K14 may beset appropriately.

A value of the evaluation value ANS1 represented by Expression abovebecomes large when the data value D11 based on the first presence timedata is large, when the data value D12 based on the second presence timedata is large, when the data value D13 based on the arrival time data inthe instruction display period is large, and when the data value D14based on the movement frequency data in the instruction display periodis large. Namely, the evaluation value ANS1 becomes larger as thepresence time of the gaze point P in the task feature area A is longer,as the presence time of the gaze point P in the instruction area B isshorter, as the arrival time at which the gaze point P arrives at thetask feature area A after the start time of the instruction displayperiod is shorter, and as the number of movement of the gaze point Pbetween the task feature area A and the instruction area B is smaller.

In contrast, the value of the evaluation value ANS1 becomes smaller whenthe data value D11 based on the first presence time data is small, whenthe data value D12 based on the second presence time data is small, whenthe data value D13 based on the arrival time data in the instructiondisplay period is small, and when the data value D14 based on themovement frequency data in the instruction display period is small.Namely, the evaluation value ANS1 becomes smaller as the presence timeof the gaze point P in the task feature area A is shorter, as thepresence time of the gaze point P in the instruction area B is longer,as the arrival time at which the gaze point P arrives at the taskfeature area A after the start time of the instruction display period islonger, and as the number of movement of the gaze point P between thetask feature area A and the instruction area B is larger.

Therefore, the evaluation unit 224 is able to obtain the evaluation databy determining whether the evaluation value ANS1 is greater than orequal to a predetermined value. For example, when the evaluation valueANS1 is greater than or equal to the predetermined value, it is possibleto evaluate that the subject is less likely to have cognitive functionalimpairment and brain functional impairment. Furthermore, when theevaluation value ANS1 is less than the predetermined value, it ispossible to evaluate that the subject is highly likely to have cognitivefunctional impairment and brain functional impairment.

Furthermore, for example, when the positional data of the gaze point Pof the subject is detected in the target display operation, thedetermination unit 218 determines whether the gaze point P of thesubject is present in the specific feature area A1 and the multiplecomparison areas A2 to A4, and outputs the determination data.

The arithmetic unit 220 calculates, based on the determination data, thegaze point transition data in the target display period that indicatesthe transition of the gaze point P in the target display period. Thearithmetic unit 220 calculates, as the gaze point transition data in thetarget display period, the presence time data in the target display, themovement frequency data in the target display period, the final areadata, and the arrival time data in the target display period.

The presence time data in the target display period indicates thepresence time in which the gaze point P is present in the specificfeature area A1. In the embodiment, when the determination unit 218determines whether the gaze point P is present in the specific featurearea A1 at, for example, regular intervals, it is possible to estimatethat the presence time in which the gaze point P is present in thespecific feature area A1 is longer as the number of determination thatthe gaze point P is present in the specific feature area A1 isincreased. Therefore, it is possible to regard the presence time data inthe target display period as the number of the determination by thedetermination unit 218 that the gaze point P is present in the specificfeature area A1. Namely, the arithmetic unit 220 is able to regard acount value CNTA1 of the counter as the presence time data in the targetdisplay period.

The movement frequency data in the target display period indicates thenumber of movement of the position of the gaze point P between themultiple comparison areas A2 to A4 before the gaze point P first arrivesat the specific feature area A1. Therefore, the arithmetic unit 220 isable to count the number of movement of the gaze point P in the areasbetween the specific feature area A1 and the comparison areas A2 to A4and use the count result before the gaze point P arrives at the specificfeature area A1 as the movement frequency data in the target displayperiod.

Furthermore, the final area data indicates an area in which the gazepoint P is finally present among the specific feature area A1 and thecomparison areas A2 to A4 in the target display period, i.e., an areathat is gazed at by the subject as the answer. The arithmetic unit 220updates the area in which the gaze point P is present every time thegaze point P is detected and is thus able to use the detection result atthe end of the target display period as the final area data.

Furthermore, the arrival time data in the target display periodindicates a period of time from a start time of the target displayperiod to an arrival time at which the gaze point P first arrives at thespecific feature area A1. Therefore, by measuring an elapsed time

from the start of the target display period by the timer T1, anddetecting a measurement value of the timer T1 when the gaze point Pfirst arrives at the specific feature area A1 with setting a flag valueto 1, the arithmetic unit 220 is able to use a detection result thetimer T1 as the arrival time data in the target display period.

Regarding the target display operation, the evaluation unit 224 obtainsthe evaluation data based on the presence time data in the targetdisplay period, the movement frequency data in the target displayperiod, the final area data, and the arrival time data in the targetdisplay period.

Here, a data value based on the final area data is denoted by D21, adata value based on the presence time data in the target display periodis denoted by D22, a data value based on the arrival time data in thetarget display period is denoted by D23, and a data value based on themovement frequency data in the target display period is denoted by D24.However, the data value D21 based on the final area data is set to 1 ifthe gaze point P of the subject is finally present in the specificfeature area A1 (i.e., in a case of a correct answer), and set to 0 ifthe gaze point P of the subject is finally not present in the specificfeature area A1 (i.e., in a case of an incorrect answer). Furthermore,it is assumed that the data value D22 based on the presence time data inthe target display period is the number of seconds in which the gazepoint P is present in the specific feature area A1. Furthermore,regarding the data value D22, it may also be possible to set an upperlimit value that is a smaller number of seconds than the display period.Furthermore, the data value D23 based on the arrival time data in thetarget display period is set to an inverse number of the arrival time(for example, 1/(arrival time)/10) (10 is a coefficient for setting anarrival time evaluation value to 1 or less based on an assumption that aminimum value of the arrival time is 0.1 second). Furthermore, the countvalue is used as it is as the data value D24 based on the movementfrequency data in the target display period. Furthermore, it may also bepossible to appropriately set an upper limit value for the data valueD24.

In this case, the evaluation value ANS is able to be represented, forexample, as follows;

ANS 2 = D 21 ⋅ K 21 + D 22 ⋅ K 22 + D 23 ⋅ K 23 + D 24 ⋅ K 24

K21 to K24 are constants for weighting. The constants K21 to K24 may beappropriately set.

A value of the evaluation value ANS2 represented by Expression abovebecomes large when the data value D21 based on the final area data isset to 1, when the data value D22 based on the presence time data in thetarget display period is large, when the data value D23 based on thearrival time data in the target display period is large, and when thevalue of the data value D24 based on the movement frequency data in thetarget display period is large. Namely, the evaluation value ANS2becomes larger when the gaze point P is finally present in the specificfeature area A1, when the presence time of the gaze point P in thespecific feature area A1 is longer, when the arrival time at which thegaze point P arrives at the specific feature area A1 after the starttime of the target display period is shorter, and when the number ofmovement of the gaze point P among the individual areas is larger.

In contrast, the value of the evaluation value ANS2 becomes smaller whenthe data value D21 based on the final area data is 0, when the datavalue D22 based on the presence time data in the target display periodis small, when the data value D23 based on the arrival time data in thetarget display period is small, and when the data value D24 based on themovement frequency data in the target display period is small. Namely,the evaluation value ANS2 becomes smaller when the gaze point P isfinally not present in the specific feature area A1, when the presencetime of the gaze point P in the specific feature area A1 is shorter,when the arrival time at which the gaze point P arrives at the specificfeature area A1 after the start time of the target display period islonger, and when the number of movement of the gaze point P among theareas is smaller.

Therefore, the evaluation unit 224 is able to obtain the evaluation databy determining whether the evaluation value ANS2 is greater than orequal to the predetermined value. For example, when the evaluation valueANS2 is greater than or equal to the predetermined value, it is possibleto evaluate that the subject is less likely to have cognitive functionalimpairment and brain functional impairment. Furthermore, when theevaluation value ANS2 is less than the predetermined value, it ispossible to evaluate that the subject is highly likely to have cognitivefunctional impairment and brain functional impairment.

Furthermore, the evaluation unit 224 is able to store the evaluationvalue ANS2 in the storage 222. For example, it may also be possible tocumulatively store the evaluation value ANS2 for the same subject andperform evaluation by comparing with the past evaluation values. Forexample, when the evaluation value ANS2 is higher than the pastevaluation value, it is possible to evaluate that a cognitive functionand a brain function have improved. Furthermore, when a cumulative valueof the evaluation value ANS2 is gradually increased, it is possible toevaluate that the cognitive function and the brain function havegradually improved.

Furthermore, the evaluation unit 224 may also be able to performevaluation by using the presence time data in the target display period,the movement frequency data in the target display period, the final areadata, and the arrival time data in the target display periodindividually or in combination. For example, when the gaze point Paccidentally arrives at the specific feature area A1 while the multipletarget objects are viewed, the data value D24 based on the movementfrequency data in the target display period becomes small. In this case,it is possible to perform evaluation together with the data value D22based on the presence time data in the target display period describedabove. For example, when the number of movement is small but thepresence time is long, it is possible to evaluate that the subject cangaze at the specific feature area A1 that is a correct answer.Furthermore, when the number of movement is small and the presence timeis also short, it is possible to evaluate that the gaze point P hasaccidentally passed through the specific feature area A1.

Furthermore, when the number of movement is small and the final area isthe specific feature area A1, it is possible to evaluate that, forexample, the gaze point P arrives at the specific feature area A1 thatis the correct answer with a smaller number of movement. In contrast,when the number of movement described above is small and the final areais not the specific feature area A1, it is possible to evaluate that,for example, the gaze point P has accidentally passed through thespecific feature area A1.

Furthermore, the evaluation unit 224 may also be possible to performevaluation by using, in combination, the evaluation value ANS1 in theinstruction display operation and the evaluation value ANS2 in thetarget display operation.

In the embodiment, when the evaluation unit 224 outputs the evaluationdata, the output controller 226 is able to allow the output device 50 tooutput, in accordance with the evaluation data, character dataindicating that, for example, “it seems that the subject is less likelyto have cognitive functional impairment and brain functional impairment”or character data indicating that “it seems that the subject is highlylikely to have cognitive functional impairment and brain functionalimpairment”. Furthermore, when the evaluation value ANS for the samesubject becomes higher than the past evaluation value ANS, the outputcontroller 226 is able to allow the output device 50 to output characterdata indicating that “a cognitive function and a brain function haveimproved” or the like.

FIG. 10 is a diagram illustrating another example of content displayedon the display 101S in the instruction display operation. As illustratedin FIG. 10, the display controller 202 simultaneously displays, in theinstruction display operation, a task target object M02 on the display101S and instruction information 12 for instructing the subject to gazeat the same figure as the task target object M02 on the display 101S.The task target object M02 is a pattern that is formed by multiple sameshapes (for example, a pentagon). Specifically, the task target objectM02 has a shape of a combination of two pentagons, and one of the cornerportions of the one pentagon overlaps with that of the other pentagon.In the task target object M02, the overlapping portion in which one ofthe corner portions of the one pentagon overlaps with that of the otherpentagon is a portion that can be an appearance feature when the subjectmemorizes the portion, i.e., the task feature portion C02.

The area setting unit 216 sets a task feature area A in the rectangularregion that includes, for example, the task feature portion C02 of thetask target object M02. Furthermore, the area setting unit 216 sets aninstruction area B in the rectangular region that includes, for example,the instruction information 12. The area setting unit 216 sets the taskfeature area A and the instruction area B on the display 101S such thatthe areas do not overlap with each other.

FIG. 11 is a diagram illustrating another example of a case in whichmultiple target objects are displayed on the display 101S in the targetdisplay operation. After the instruction display operation, the displaycontroller 202 displays, in the target display operation, as illustratedin FIG. 11, a specific target object M5 that is a correct answer to theinstruction information 12 and the comparison target objects M6 and M7that are incorrect answers to the instruction information 12.

Similarly to the above description, based on a content of theinstruction information 12, the task target object M02 and the specifictarget object M5 are the same target objects in appearance. Therefore,similarly to the task target object M02, the specific target object M5has a shape of a combination of two pentagons and one of the cornerportions of the one pentagon overlaps that of the other pentagon.Furthermore, similarly to the specific target object M5, the comparisontarget objects M6 and M7 each have a shape of a combination of twopentagons. However, each of the comparison target objects M6 and M7 hasa shape in which the corner portions that are different from those inthe specific target object M5 overlap with each other.

The area setting unit 216 is able to set a specific feature area A1 fora specific feature portion C5 of the specific target object M5 and isable to set comparison areas A2 and A3 for the comparison target objectsM6 and M7, respectively. The specific feature portion C5 corresponds toa portion for the task feature portion C02 of the task target objectM02. Here, the specific feature portion C5 of the specific target objectM5 corresponds to the same portion as the task feature portion C02 ofthe task target object M02. Namely, in the specific target object M5,the overlapping portion in which one of the corner portions of the onepentagon overlaps with that of the other pentagon is the specificfeature portion C5. The area setting unit 216 sets the specific featurearea A1 and the comparison areas A2 and A3 on the display 101S so as notto overlap with each other. In this way, in the target displayoperation, by displaying the specific target object M5 and thecomparison target objects M6 and M7 that are similar figures, it is alsopossible to perform evaluation related to a figure recognition functionof the subject.

FIG. 12 is a diagram illustrating another example of the content that isdisplayed on the display 101S in the instruction display operation. Asillustrated in FIG. 12, in the instruction display operation, thedisplay controller 202 simultaneously displays a task target object M03on the display 101S and instruction information 13 for instructing thesubject to gaze at the same figure as the task target object M03 on thedisplay 101S. The task target object M03 is a pattern that is obtainedby bilaterally and symmetrically arranging two heart shapes each ofwhich is rotated by, for example, 90° and deleting lines of anoverlapping portion from a shape in which each of protruding endportions overlaps. In this case, the overlapping portion of the twoheart shapes corresponds to a recess portion in appearance. In the tasktarget object M03, this kind of recess portion can be an appearancefeature when the subject memorizes the portion, i.e., the task featureportion C03.

The area setting unit 216 sets a task feature area A in the rectangularregion that includes, for example, the task feature portion C03 of thetask target object M03. Furthermore, the area setting unit 216 sets aninstruction area B in the rectangular region that includes, for example,the instruction information 13. The area setting unit 216 sets the taskfeature area A and the instruction area B on the display 101S such thatthese areas do not overlap with each other.

FIG. 13 is a diagram illustrating another example in a case in whichmultiple target objects are displayed on the display 101S in the targetdisplay operation. After the instruction display operation, asillustrated in FIG. 13, the display controller 202 displays, in thetarget display operation, a specific target object M8 that is a correctanswer to the instruction information 13 and the comparison targetobjects M9 to M11 that is incorrect answers to the instructioninformation 13.

Similarly to the above description, based on the content of theinstruction information 13, the task target object M03 and the specifictarget object M8 are the same target object in appearance. Therefore,similarly to the task target object M03, the specific target object M8is a pattern that is obtained by bilaterally and symmetrically arrangingtwo heart shapes each of which is rotated by, for example, 90° anddeleting the lines of the overlapping portion from the shape in whicheach of the protruding end portions overlaps. Furthermore, similarly tothe specific target object M8, the comparison target objects M9 to M11are patterns each of which is obtained by deleting the lines of theoverlapping portion from the shape that is obtained by bilaterally andsymmetrically arranging two figures. The comparison target object M9 isa pattern based on circles, the comparison target object M10 is apattern based on quadrilaterals, the comparison target object M11 is apattern based on triangles.

The area setting unit 216 is able to set a specific feature area A1 fora specific feature portion C8 of the specific target object M8 and isable to set comparison areas A2 to A4 for the comparison target objectsM9 to M11 respectively. The specific feature portion C8 corresponds to aportion for the task feature portion C03 of the task target object M03.Here, the specific feature portion C8 of the specific target object M8corresponds to the same portion as the task feature portion C03 of thetask target object M03. Namely, in the specific target object M8, therecess portion that is formed by the overlapping portion of the twoheart shapes corresponds to the specific feature portion C8. The areasetting unit 216 sets the specific feature area A1 and the comparisonareas A2 to A4 on the display 101S such that these areas do not overlapwith each other. In this way, in the target display operation, bydisplaying the specific target object M8 and the comparison targetobjects M9 to M11 that are similar figures, it is possible to evaluate afigure recognition function of the subject.

In the following, an example of the evaluation method according to theembodiment will be described. FIG. 14 and FIG. 15 are flowcharts eachillustrating an example of the evaluation method according to theembodiments. In the embodiments, a description will be given of anexample of the evaluation method in a case in which the instructiondisplay operation and the target display operation are consecutivelyperformed. An example of the instruction display operation is mainlyillustrated in FIG. 14 and an example of the target display operation isillustrated in FIG. 15.

As illustrated in FIG. 14, in the instruction display operation, thedisplay controller 202 starts a playback of a video (Step S101), andthen, resets the timer T1 (Step S102), resets count values CNTA and CNTBof the counter (Step S103), and sets a flag value F to zero (Step S104).

The gaze point detecting unit 214 detects a positional data of the gazepoint P of the subject on the display 101S of the display device 101 foreach defined sampling period (for example, 20 (msec)) while showing thevideo displayed on the display device 101 to the subject (Step S105).When the positional data has been detected (No at Step S106), thedetermination unit 218 determines, based on the positional data, thearea in which the gaze point P is present (Step S107). Furthermore, whenthe positional data is not detected (Yes at Step S106), the process atStep S119 and the subsequent processes, which will be described later,are performed.

When it is determined that the gaze point P is present in the taskfeature area A (Yes at Step S108), the arithmetic unit 220 determineswhether the flag value F is 1, i.e., whether the gaze point P arrives atthe task feature area A for the first time (1: has already arrived, 0:has not arrived yet) (Step S109). When the flag value F is 1 (Yes atStep S109), the arithmetic unit 220 skips the subsequent processes atStep S110 and Step S111 and performs the process at Step S112 that willbe described later.

Furthermore, when the flag value F is not 1, i.e., the gaze point Parrives at the task feature area A for the first time (No at Step S109),the arithmetic unit 220 extracts the measurement result of the timer T1as the arrival time data in the instruction display period (Step S110).After that, the arithmetic unit 220 changes the flag value to 1 (StepS111).

Then, the arithmetic unit 220 determines whether the area in which thegaze point P is present at the latest detection, i.e., the final area,is the task feature area A (Step S112). When the arithmetic unit 220determines that the final area is the task feature area A (Yes at StepS112), the arithmetic unit 220 skips the subsequent process at Step S113and performs the process at Step S114 that will be described later.Furthermore, when it is determined that the final area is not the taskfeature area A (No at Step S112), the arithmetic unit 220 increments anintegrated number that indicates the number of movement of the gazepoint P among the areas by 1 (Step S113), and increments the count valueCNTA that indicates the first presence time data in the task featurearea A by 1 (Step S114). After that, the arithmetic unit 220 performsthe process at Step S119 and the subsequent processes that will bedescribed later.

Furthermore, when it is determined that the gaze point P is not presentin the task feature area A (No at Step S108), the arithmetic unit 220determines whether the gaze point P is present in the instruction area B(Step S115). When it is determined that the gaze point P is present inthe instruction area B (Yes at Step S115), the arithmetic unit 220determines whether the area in which the gaze point P is present at thelatest detection, i.e., the final area, is the instruction area B (StepS116). When the arithmetic unit 220 determines that the final area isthe instruction area B (Yes at Step S116), the arithmetic unit 220 skipsthe subsequent process at Step S117 and performs the process at StepS118 that will be described later. Furthermore, when it is determinedthat the final area is not the instruction area B (No at Step S116), thearithmetic unit 220 increments an integrated number that indicates thenumber of movement of the gaze point P among the areas by 1 (Step S117),and increments the count value CNTB that indicates the second presencetime data in the instruction area B by 1 (Step S118). After the processat Step S118, and when it is determined that the gaze point P is notpresent in the instruction area B at the process at Step S115 (No atStep S115), the arithmetic unit 220 performs the process at Step S119and the subsequent processes that will be described later.

After that, the arithmetic unit 220 determines, based on the detectionresult of the detection timer T1, whether the time reaches a completiontime of the playback of the video (Step S119). When it is determined, bythe arithmetic unit 220, that the time does not reach the completiontime of the playback of the video (No at Step S119), the arithmetic unit220 repeatedly performs the process at Step S105 and the subsequentprocesses described above.

When it is determined, by the arithmetic unit 220, that the time reachesthe completion time of the playback of the video (Yes at Step S119), thetarget display operation is performed (Step S200). As illustrated inFIG. 15, in the target display operation, the display controller 202starts a playback of a video (Step S201). After an elapse of a waitingtime to an evaluation purpose video portion (Step S202), the displaycontroller 202 resets a timer TT1 (Step S203), resets a count valueCNTA1 of the counter (Step S204), and sets a flag value FF to 0 (StepS205).

The gaze point detecting unit 214 detects a positional data of the gazepoint P of the subject on the display 101S of the display device 101 foreach defined sampling period (for example, 20 (msec)) while showing thevideo displayed on the display device 101 to the subject (Step S206).When the positional data is not detected (Yes at Step S207), thearithmetic unit 220 performs the process at Step S230 and the subsequentprocesses that will be described later. When the positional data hasbeen detected (No at Step S207), the determination unit 218 determines,based on the positional data, the area in which the gaze point P ispresent (Step S208).

When it is determined that the gaze point P is present in the specificfeature area A1 (Yes at Step S209), the arithmetic unit 220 determineswhether the flag value FF is 1, i.e., whether the gaze point P arrivesat the specific feature area A1 for the first time (1: has alreadyarrived, 0: has not arrived yet) (Step S210). When the flag value FF is1 (Yes at Step S210), the arithmetic unit 220 skips the subsequentprocesses at Step S211 to Step S213 and performs the process at StepS214 that will be described later.

Furthermore, when the flag value FF is not 1, i.e., when the gaze pointP arrives at the specific feature area A1 for the first time (No at StepS210), the arithmetic unit 220 extracts the measurement result of thetimer TT1 as the arrival time data in the target display period (StepS211). Furthermore, the arithmetic unit 220 allows the storage 222 tostore the movement frequency data in the target display period thatindicates the number of movement of the gaze point P among the areasbefore the gaze point P arrives at the specific feature area A1 (StepS212). After that, the arithmetic unit 220 changes the flag value FF to1 (Step S213).

Then, the arithmetic unit 220 determines whether the area in which thegaze point P is present at the latest detection, i.e., the final area,is the specific feature area A1 (Step S214). When the arithmetic unit220 determines that the final area is the specific feature area A1 (Yesat Step S214), the arithmetic unit 220 skips the processes at Step S215and Step S216 and performs the process at Step S217 and the subsequentprocesses that will be described later. Furthermore, when it isdetermined that the final area is not the specific feature area A1 (Noat Step S214), the arithmetic unit 220 increments an integrated numberthat indicates the number of movement of the gaze point P among theareas by 1 (Step S215), and changes the final area to the specificfeature area A1 (Step S216). Furthermore, the arithmetic unit 220increments the count value CNTA1 that indicates the presence time datain the target display period in the specific feature area A1 by 1 (StepS217). After that, the arithmetic unit 220 performs the process at StepS230 and the subsequent processes that will be described later.

Furthermore, when it is determined that the gaze point P is not presentin the specific feature area A1 (No at Step S209), the arithmetic unit220 determines whether the gaze point P is present in the comparisonarea A2 (Step S218). When it is determined that the gaze point P ispresent in the comparison area A2 (Yes at Step S218), the arithmeticunit 220 determines whether the area in which the gaze point P ispresent at the latest detection, i.e., the final area, is the comparisonarea A2 (Step S219). When the arithmetic unit 220 determines that thefinal area is the comparison area A2 (Yes at Step S219), the arithmeticunit 220 skips the subsequent processes at Step S220 and Step S221 andperforms the process at Step S230 that will be described later.Furthermore, when it is determined that the final area is not thecomparison area A2 (No at Step S219), the arithmetic unit 220 incrementsan integrated number that indicates the number of movement of the gazepoint P among the areas by 1 (Step S220), and changes the final area tothe comparison area A2 (Step S221). After that, the arithmetic unit 220performs the process at Step S230 and the subsequent processes whichwill be described later.

Furthermore, when it is determined that the gaze point P is not presentin the comparison area A2 (No at Step S218), the arithmetic unit 220determines whether the gaze point P is present in the comparison area A3(Step S222). When it is determined that the gaze point P is present inthe comparison area A3 (Yes at Step S222), the arithmetic unit 220determines whether the area in which the gaze point P is present at thelatest detection, i.e., the final area, is the comparison area A3 (StepS223). When the arithmetic unit 220 determines that the final area isthe comparison area A3 (Yes at Step S223), the arithmetic unit 220 skipsthe subsequent processes at Step S224 and Step S225 and performs theprocess at Step S230 that will be described later. Furthermore, when itis determined that the final area is not the comparison area A3 (No atStep S223), the arithmetic unit 220 increments an integrated number thatindicates the number of movement of the gaze point P among the areas by1 (Step S224), and changes the final area to the comparison area A3(Step S225). After that, the arithmetic unit 220 performs the process atStep S230 and the subsequent processes that will be described later.

Furthermore, when it is determined that the gaze point P is not presentin the comparison area A3 (No at Step S222), the arithmetic unit 220determines whether the gaze point P is present in the comparison area A4(Step S226). When it is determined that the gaze point P is present inthe comparison area A4 (Yes at Step S226), the arithmetic unit 220determines whether the area in which the gaze point P is present at thelatest detection, i.e., the final area, is the comparison area A4 (StepS227). When the arithmetic unit 220 determines that the final area isthe comparison area A4 (Yes at Step S227), the arithmetic unit 220 skipsthe subsequent processes at Step S228 and Step S229 and performs theprocess at Step S230 that will be described later. Furthermore, when itis determined that the final area is not the comparison area A4 (No atStep S227), the arithmetic unit 220 increments an integrated number thatindicates the number of movement of the gaze point P among the areas by1 (Step S228), and changes the final area to the comparison area A4(Step S229). After the process at Step S229, and when it is determined,at Step S226, that the gaze point P is not present in the comparisonarea A4 (No at Step S226), the arithmetic unit 220 performs the processat Step S230 and the subsequent processes that will be described later.

After that, the arithmetic unit 220 determines, based on the detectionresult of the detection timer TT1, whether the time reaches a completiontime of the playback of the video (Step S230). When it is determined, bythe arithmetic unit 220, that the time does not reach the completiontime of the playback of the video (No at Step S230), the arithmetic unit220 repeatedly performs the process at Step S206 and the subsequentprocesses described above.

When it is determined, by the arithmetic unit 220, that the time reachesthe completion time of the playback of the video (Yes at Step S230), thetarget display operation has been completed. After the completion of thetarget display operation, as illustrated in FIG. 14, the displaycontroller 202 stops the playback of the video for the instructiondisplay operation (Step S120). After the playback of the video isstopped, the evaluation unit 224 calculates the evaluation value that isobtained from the processing result described above, and obtainsevaluation data based on the evaluation value (Step S121). At Step S121,the evaluation unit 224 calculates the evaluation value ANS1 based on,for example, the first presence time data, the second presence timedata, the movement frequency data in the instruction display period, andthe arrival time data in the instruction display period that areobtained from the processing result in the instruction display operation(Step S121), and obtains the evaluation data based on the evaluationvalue ANS1 Furthermore, the evaluation unit 224 calculates theevaluation value ANS2 based on, for example, the presence time data inthe target display period, the movement frequency data in the targetdisplay period, the final area data, and the arrival time data in thetarget display period that are obtained from the processing result inthe target display operation (Step S121), and obtains the evaluationdata based on the evaluation value ANS2. After that, the outputcontroller 226 outputs the evaluation data by the evaluation unit 224(Step S122). Furthermore, in the example described above, a case inwhich the evaluation data is output after the instruction displayoperation and the target display operation are consecutively performedhas been described. However, the case is not limited to this and it mayalso be possible to perform an evaluation every time each of theinstruction display operation and the target display operation has beencompleted.

Furthermore, in the embodiment described above, a description has beengiven with a case, as an example, in which the area setting unit 216sets, in the target display operation, the specific feature area A1 inthe specific feature area of the specific target object. In contrast, inthe target display operation, the area setting unit 216 may also set thespecific feature area A1 for the specific feature area of the specifictarget object and a specific area for an entirety of the specific targetobject.

FIG. 16 to FIG. 18 are diagrams each illustrating an example of a casein which, in the respective target display operations illustrated inFIG. 9, FIG. 11, and FIG. 13, a specific area for an entirety of thespecific target object is set in addition to the specific feature areaA1 for the specific feature area of the specific target object. Asillustrated in FIG. 16, an area setting unit 215 is able to set, in thetarget display operation, a specific area A5 in the rectangular regionfor an entirety of the specific target object M1 in addition to thespecific feature area A1 for the specific feature portion C1 of thespecific target object M1. Furthermore, as illustrated in FIG. 17, thearea setting unit 215 is able to set, in the target display operation, aspecific area A5 in the rectangular region for an entirety of thespecific target object M5 in addition to the specific feature area A1for the specific feature portion C5 of the specific target object M5.Furthermore, as illustrated in FIG. 18, the area setting unit 215 isable to set, in the target display operation, a specific area A5 in therectangular region for an entirety of the specific target object M8 inaddition to the specific feature area A1 for the specific featureportion C8 of the specific target object M8. Furthermore, the shape ofeach of the specific areas A5 illustrated in FIG. 16 to FIG. 18 is notlimited to a rectangle and may also be another shape, such as a circularshape, an elliptical shape, or a polygonal shape.

FIG. 19 is a flowchart illustrating another example of the evaluationmethod according to the embodiments. FIG. 19 illustrates an operation ofperforming, in the target display operation, a determination in a casein which a specific area for the entirety of the specific target objectis set in addition to the specific feature area A1 for the specificfeature area of the specific target object.

As illustrated in FIG. 19, similarly to the embodiments described above,the display controller 202 starts, in the target display operation, aplayback of a video (Step S201). After the elapse of the waiting time tothe evaluation purpose video portion (Step S202), the display controller202 resets the timer TT1 (Step S203), resets the count value CNTA1 ofthe counter (Step S204), and sets the flag value FF to 0 (Step S205).The gaze point detecting unit 214 detects the positional data of thegaze point P of the subject on the display 101S of the display device101 (Step S206). When the positional data is detected (No at Step S207),the determination unit 218 determines, based on the positional data, thearea in which the gaze point P is present (Step S208).

In the embodiments described above, a determination whether or not thegaze point P is present in the specific feature area A1 has beenperformed. However, here, a determination whether or not the gaze pointP is present in the specific area A5 is performed (Step S231). When itis determined that the gaze point P is not present in the specific areaA5 (No at Step S231), similarly to the embodiments described above, theprocess at Step S218 and the subsequent processes are performed. In thiscase, the content of the process at Step S218 and the subsequentprocesses is the same as that described in the embodiments above.

In contrast, when it is determined that the gaze point P is present inthe specific area A5 (Yes at Step S231), the arithmetic unit 220determines whether the flag value FF is 1, i.e., whether the gaze pointP arrives at specific area A5 for the first time (1: has alreadyarrived, 0: has not arrived yet) (Step S232). When the flag value FF is1 (Yes at Step S232), the arithmetic unit 220 skips the subsequentprocesses at Step S233 to Step S235 and performs the process at StepS236 that will be described later.

Furthermore, when the flag value FF is not 1, i.e., when the gaze pointP arrives at the specific area A5 for the first time (No at Step S232),the arithmetic unit 220 extracts the measurement result of the timer TT1as the arrival time data in the target display period (Step S233).Furthermore, the arithmetic unit 220 allows the storage 222 to store themovement frequency data in the target display period that indicates thenumber of movement of the gaze point P among the areas before the gazepoint P arrives at the specific area A5 (Step S234). After that, thearithmetic unit 220 changes the flag value FF to 1 (Step S235).

Then, the arithmetic unit 220 determines whether the area in which thegaze point P is present at the latest detection, i.e., the final area,is the specific area A5 (Step S236). When the arithmetic unit 220determines that the final area is the specific area A5 (Yes at StepS236), the arithmetic unit 220 skips the subsequent processes at StepS237 and Step S238 and performs the process at Step S239 that will bedescribed later. Furthermore, when it is determined that the final areais not the specific area A5 (No at Step S236), the arithmetic unit 220increments the integrated number that indicates the number of movementof the gaze point P among the areas by 1 (Step S237), and changes thefinal area to the specific area A5 (Step S238). Furthermore, thearithmetic unit 220 increments the count value CNTA1 that indicates thepresence time data in the target display period in the specific area A5by 1 (Step S239).

After that, the arithmetic unit 220 performs a determination whether ornot the gaze point P is present in the specific feature area A1 (StepS240). When it is determined that the gaze point P is present in thespecific feature area A1 (Yes at Step S240), the arithmetic unit 220increments the count value CNTA1 that indicates the presence time datain the target display period in the specific area A5 by 1 (Step S241).In contrast, when it is determined that the gaze point P is not presentin the specific feature area A1 (No at Step S240), the arithmetic unit220 skips the process at Step S241 and performs the process at Step S230and the subsequent processes.

Namely, when it is determined that the gaze point P is present in thespecific feature area A1, in also at Step S241 in addition to theprocess at Step S239, the count value CNTA1 that indicates the presencetime data in the target display period is incremented by 1. Therefore,when it is determined that the gaze point P is present in the specificfeature area A1, the count value CNTA1 that indicates the presence timedata in the target display period is totally incremented by 2. Incontrast, when it is determined that the gaze point P is present in thespecific area A5 but is not present in the specific feature area A1, atStep S239, the count value CNTA1 that indicates the presence time datain the target display period is incremented by 1. However, at Step S241,the count value CNTA1 is not incremented by 1. Therefore, when it isdetermined that the gaze point P is present in the specific area A5 butis not present in the specific feature area A1, the count value CNTA1that indicates the presence time data in the target display period isincremented by 1. In this way, different weightings are applied to thepresence time data in the target display period between in a case inwhich it is determined that the gaze point P is present in the specificfeature area A1 and in a case in which it is determined that the gazepoint P is present in the specific area A5 but is not present in thespecific feature area A1.

As described above, the evaluation device 100 according to the presentapplication includes: a display 101S configured to display images; agaze point detecting unit 214 configured to detect a positional data ofa gaze point of a subject who observes the display 101S; a displaycontroller 202 configured to display a task target object that includesa task feature portion and that is to be gazed at by the subject andinstruction information that is a task related to the task target objecton the display 101S, and to display, after displaying the task targetobject and the instruction information, a specific target object thatincludes a specific feature portion corresponding to the task featureportion and that is a correct answer to the instruction information andcomparison target objects each of which differs from the specific targetobject on the display 101S; an area setting unit 216 configured to set aspecific feature area A1 for the specific feature portion and comparisonareas A2 to A4 for the comparison target objects on the display 101S; adetermination unit 218 configured to determine, based on the positionaldata of the gaze point, whether the gaze point is present in each of thespecific feature area A1 and the comparison areas A2 to A4; anarithmetic unit 202 configured to calculate, based on a determinationresult by the determination unit 218, a gaze point transition data in atarget display period; and an evaluating unit 224 configured to obtain,based on the gaze point transition data in the target display period, anevaluation data of the subject.

Furthermore, the evaluation method according to the present applicationincludes: displaying images on a display 101S; detecting a positionaldata of a gaze point of a subject who observes the display 101S;displaying a task target object that includes a task feature portion andthat is to be gazed at by the subject and instruction information thatis a task related to the task target object on the display 101S, anddisplaying, after displaying the task target object and the instructioninformation, a specific target object that includes a specific featureportion corresponding to the task feature portion and that is a correctanswer to the instruction information and comparison target objects eachof which differs from the specific target object on the display 101S;setting a specific feature area A1 for the specific feature portion andcomparison areas A2 to A4 for the comparison target objects on thedisplay 101S; determining, based on the positional data of the gazepoint, whether the gaze point is present in each of the specific featurearea A1 and the comparison areas A2 to A4; calculating, based on adetermination result, a gaze point transition data in a target displayperiod; and obtaining, based on the gaze point transition data in thetarget display period, an evaluation data of the subject.

Furthermore, the non-transitory storage medium according to the presentapplication stores the evaluation program that causes a computer toexecute: a process of displaying images on a display 101S; a process ofdetecting a positional data of a gaze point of a subject who observesthe display 101S; a process of displaying a task target object thatincludes a task feature portion and that is to be gazed at by thesubject and instruction information that is a task related to the tasktarget object on the display 101S, and displaying, after displaying thetask target object and the instruction information, a specific targetobject that includes a specific feature portion corresponding to thetask feature portion and that is a correct answer to the instructioninformation and comparison target objects each of which differs from thespecific target object on the display 101S; a process of setting aspecific feature area A1 for the specific feature portion and comparisonareas A2 to A4 for the comparison target objects on the display 101S; aprocess of determining, based on the positional data of the gaze point,whether the gaze point is present in each of the specific feature areaA1 and the comparison areas A2 to A4; a process of calculating, based ona determination result, a gaze point transition data in a target displayperiod; and a process of obtaining, based on the gaze point transitiondata in the target display period, an evaluation data of the subject.

According to the embodiments, by setting the specific feature area forthe specific feature portion in the target display operation, it ispossible to evaluate whether the subject makes a determination by gazingat the specific feature portion of the specific target object.Therefore, it is possible to prevent a case in which the gaze point P ofthe subject is accidentally directed to the specific target object frombeing determined as a correct answer. Accordingly, it is possible toperform evaluation of the subject with high accuracy.

Furthermore, in the evaluation device 100 according to the embodiment,each of the task feature portion and the specific feature portion is arecess portion or a protruding portion of a pattern that constituteseach of the task target object and the specific target object or aconnection portion of the multiple patterns. Since the subject is ableto easily gaze the task feature portion and the specific featureportion, it is possible to prevent a case in which the gaze point of thesubject is accidentally directed to the specific target object frombeing determined as a correct answer.

Furthermore, in the evaluation device 100 according to the embodiments,the area setting unit 216 sets the task feature area A for the taskfeature portion and the instruction area B for the instructioninformation on the display. The determination unit 218 determines, basedon the positional data of the gaze point, whether the gaze point P ispresent in each of the task feature area A and the instruction area B,and the arithmetic unit 220 calculates, based on the determinationresult by the determination unit 218, the gaze point transition data inthe instruction display period that indicates the transition of the gazepoint P. Accordingly, it is possible to evaluate the subject from aviewpoint whether, after the subject viewed the instruction informationdisplayed on the display 101S, the subject attempts to gaze at the taskfeature area A of the task target object indicated by the instructioninformation.

Furthermore, in the evaluation device 100 according to the embodiments,the area setting unit 216 further sets, on the display 101S, thespecific area A5 for the specific portion. The determination unit 218determines, based on the positional data of the gaze point P, whetherthe gaze point P is present in each of the specific feature area A1, thespecific area A5, and the comparison areas A2 to A4, and the evaluatingunit 220 obtains the evaluation data by applying different weightings toa case in which the gaze point P is present in the specific feature areaA1 and to a case in which the gaze point P is not present in thespecific feature area A1 but is present in the specific area A5.Therefore, it is possible to distinguish a case in which the subjectgazes at the specific feature portion from a case in which the subjectgazes at the specific target object that is other than the specificfeature portion. Accordingly, it is possible to perform evaluation ofthe subject with high accuracy.

The technical scope of the present embodiments is not limited to theembodiments described above and various modifications are possible aslong as they do not depart from the spirit of the present embodiments.For example, in the embodiments described above, a case has beendescribed as one example in which the area setting unit 216 sets thespecific feature area A1 by using the recess portion or the protrudingportion of the pattern that constitutes the specific target object or byusing the connection portion of the multiple patterns as the specificfeature portion. However, the embodiments are not limited thereto. Forexample, it may also be possible to set an area for the portion of thetask target object gazed at by the subject in the instruction displayoperation as the specific feature area A1.

In this case, in the instruction display operation, the gaze pointdetecting unit 214 detects the area that has been gazed at by thesubject. At this time, the gaze point detecting unit 214 obtains apositional relationship between coordinates of the portion in which thetask target object is displayed on the display 101S and coordinates ofthe area that has been gazed at by the subject. After that, in thetarget display operation, the area setting unit 216 sets the specificfeature area A1 in an area corresponding to the area detected by thegaze point detecting unit 214 among areas included in the specifictarget object displayed on the display 101S. In this case, the areasetting unit 216 sets the specific feature area A1 at a positioncorresponding to the coordinates of the portion in which the specifictarget object is displayed on the display 101S based on a relativepositional relationship between the coordinates of the portion in whichthe task target object is displayed on the display 101S and thecoordinates of the area that is gazed at by the subject.

In the following, an example of the evaluation method in this case willbe described. FIG. 20 and FIG. 21 are flowcharts each illustrating theevaluation method according to the modification. FIG. 20 mainlyillustrates an example of the instruction display operation, whereasFIG. 21 illustrates an example of the target display operation.

As illustrated in FIG. 20, in the instruction display operation, theprocesses form Step S101 to Step S119 are performed in a similar mannerto those performed in the embodiments described above. At Step S119,when it is determined, by the arithmetic unit 220, that the time reachesthe completion time of the playback of the video (Yes at Step S119), thegaze point detecting unit 214 detects the area that is gazed at by thesubject and obtains the positional relationship between the coordinatesof the detected area and the coordinates of the portion in which thetask target object is displayed (Step S130). After that, the targetdisplay operation is performed (Step S200).

As illustrated in FIG. 21, in the target display operation, theprocesses from Step S201 to Step S208 are performed in a similar mannerto those performed in the embodiments described above. After the processat Step S208 has been performed, the area setting unit 216 sets thespecific feature area A1 in an area corresponding to the area detectedby the gaze point detecting unit 214 among areas included in thespecific target object displayed on the display 101S (Step S250). Afterthat, the process at Step S209 and the subsequent processes areperformed based on the set specific feature area A1. In this case, thecontent of the process at Step S209 and the subsequent processes is thesame as that described in the embodiments above.

In this way, by using the area corresponding to the area gazed at by thesubject in the task target object as the specific feature area, it ispossible to evaluate the subject with higher accuracy from a viewpointwhether or not the subject gazes at and memorizes the task feature areaof the task target object, and whether or not the subject gazes at anddetermines the specific feature area of the specific target object.

It is possible to use the evaluation device, the evaluation method, andthe evaluation program according to the embodiment in, for example, aline-of-sight detecting device.

According to an aspect of the present application, it is possible toprovide an evaluation device, an evaluation method, and an evaluationprogram capable of evaluating cognitive functional impairment and brainfunctional impairment with high accuracy.

Although the application has been described with respect to specificembodiments for a complete and clear application, the appended claimsare not to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. An evaluation device comprising: a displayconfigured to display images; a gaze point detecting unit configured todetect a positional data of a gaze point of a subject who observes thedisplay; a display controller configured to display a task target objectthat includes a task feature portion and that is to be gazed at by thesubject and instruction information that is a task related to the tasktarget object on the display, and to display, after displaying the tasktarget object and the instruction information, a specific target objectthat includes a specific feature portion corresponding to the taskfeature portion and that is a correct answer to the instructioninformation and comparison target objects each of which differs from thespecific target object on the display; an area setting unit configuredto set a specific feature area for the specific feature portion andcomparison areas for the comparison target objects on the display; adetermination unit configured to determine, based on the positional dataof the gaze point, whether the gaze point is present in each of thespecific feature area and the comparison areas; an arithmetic unitconfigured to calculate, based on a determination result by thedetermination unit, a gaze point transition data in a target displayperiod; and an evaluating unit configured to obtain, based on the gazepoint transition data in the target display period, an evaluation dataof the subject.
 2. The evaluation device according to claim 1, whereineach of the task feature portion and the specific feature portioncorresponds to a recess portion or a protruding portion of a patternthat constitutes each of the task target object and the specific targetobject, or a connection portion of multiple patterns.
 3. The evaluationdevice according to claim 1, wherein the area setting unit is furtherconfigured to set a specific area for an entirety of the specific targetobject on the display, the determination unit is further configured todetermine, based on the positional data of the gaze point, whether thegaze point is present in each of the specific feature area, the specificarea, and the comparison areas, and the evaluating unit is furtherconfigured to obtain the evaluation data by applying differentweightings to a case in which the gaze point is present in the specificfeature area and to a case in which the gaze point is not present in thespecific feature area but is present in the specific area.
 4. Theevaluation device according to claim 1, wherein the area setting unit isfurther configured to set a task feature area for the task featureportion and an instruction area for the instruction information on thedisplay, the determination unit is further configured to determine,based on the positional data of the gaze point, whether the gaze pointis present in each of the task feature area and the instruction area,and the arithmetic unit is further configured to calculate, based on thedetermination result by the determination unit, the gaze pointtransition data in an instruction display period.
 5. An evaluationmethod comprising: displaying images on a display; detecting apositional data of a gaze point of a subject who observes the display;displaying a task target object that includes a task feature portion andthat is to be gazed at by the subject and instruction information thatis a task related to the task target object on the display, anddisplaying, after displaying the task target object and the instructioninformation, a specific target object that includes a specific featureportion corresponding to the task feature portion and that is a correctanswer to the instruction information and comparison target objects eachof which differs from the specific target object on the display; settinga specific feature area for the specific feature portion and comparisonareas for the comparison target objects on the display; determining,based on the positional data of the gaze point, whether the gaze pointis present in each of the specific feature area and the comparisonareas; calculating, based on a determination result, a gaze pointtransition data in a target display period; and obtaining, based on thegaze point transition data in the target display period, an evaluationdata of the subject.
 6. A non-transitory storage medium that stores anevaluation program that causes a computer to execute: a process ofdisplaying images on a display; a process of detecting a positional dataof a gaze point of a subject who observes the display; a process ofdisplaying a task target object that includes a task feature portion andthat is to be gazed at by the subject and instruction information thatis a task related to the task target object on the display, anddisplaying, after displaying the task target object and the instructioninformation, a specific target object that includes a specific featureportion corresponding to the task feature portion and that is a correctanswer to the instruction information and comparison target objects eachof which differs from the specific target object on the display; aprocess of setting a specific feature area for the specific featureportion and comparison areas for the comparison target objects on thedisplay; a process of determining, based on the positional data of thegaze point, whether the gaze point is present in each of the specificfeature area and the comparison areas; a process of calculating, basedon a determination result, a gaze point transition data in a targetdisplay period; and a process of obtaining, based on the gaze pointtransition data in the target display period, an evaluation data of thesubject.